1. Technical Field
The present invention relates to a composition for fabricating contact lenses. More particularly, the composition for fabricating contact lenses comprising a fluoro-containing ether monomer.
2. Description of Related Art
In the early years hard contact lenses were mainly made of glass. The soft contact lenses were therefore developed to improve the discomfort of wearing of the hard contact lenses. The soft contact lenses can be classified into two categories, hydrogel contact lenses and silicone hydrogel contact lenses.
The hydrogel contact lenses are made from hydrogel materials, such as poly-2-hydroxyethyl methacrylate (p-HEMA). Since the water content of the p-HEMA is only about 38.8%, one or more than one kinds of the hydrophilic monomer, for example N-vinylpyrrolidone (NVP), N,N-dimethylacrylamide (DMA) and methyl acrylic acid (MAA), are added to enhance the water content of such materials for the contact lenses.
With the addition of the hydrophilic monomer, the water content of the contact lenses can increase up to 80%. However, the higher water content of the contact lens is, the lower tension and toughness thereof become. Therefore, the water content of contact lenses is generally controlled in the range from about 45% to 58% to have a sufficient mechanical strength for the contact lenses.
For improving the disadvantages of the hydrogel contact lenses, silicone contact lenses with excellent oxygen permeability (DK) have been studied for a number of years. The silicone hydrogel contact lenses are made by polymerizing a hydrophilic silicone polymeric material and a hydrophilic monomer.
However, the lipid secreted from the human eyes would produce lipid deposition on the contact lenses and result in discomfort when wearing. It is known in the prior art that the fluorosilicone acrylate is suitable for manufacturing contact lenses because of having high oxygen permeability, which can reduce corneal disease from hypoxia. In addition, the contact lenses also provide comfort of wearing and not to absorb ocular secretions. But the disadvantage of the contact lenses is poor in flexibility.
Thus, the present invention provides a novel fluoro-containing ether monomer for fabricating contact lenses and the contact lenses fabricating therefrom have desirable physical properties and is comfortable in wearing.